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(No Model.) 3 Sheets-S heet 1.

J. A. BRILL & W. S. ADAMS. DIFFERENTIAL BRAKE MECHANISM.

N0. 603,723. Patented May10, 1898.

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Patented May 10,1898.

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DIFFERENTIAL BRAKE MECHANISM.

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(No Model.)

DIFFERENTIAL BRAKE MECHANISM.

No. 603,723. Patented May 10,1898.

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UNITED A STATES PATENT OFFICE.

JOHN A. BRILL AND WALTER S. ADAMS, OF PHILADELPHIA, PENNSYLVANIA; SAID ADAMS ASSIGNOR TO SAID BRILL.

DIFFERENTIAL BRAKE MECHANISM.

SPECIFICATION forming part of Letters Patent No. 603,723, dated May 10, 1898.

Application filed a c 3, 1897.

.for street or other cars.

Our invention has for its objects to provide in a brake mechanism means whereby the power exerted by the brake mechanism can be graduated during its application to the faces or treads of the wheels of the truck and also to prevent the skidding of the wheels on the track. One of the special objects of our invention in this regard is to provide means for applying this graduated braking power or force either to what are termed the trailing or guide? wheels of trucks in which sets of wheels of large and small diameter are employed, or to both the driving and trail wheels,

or to theIdriving-wheels alone, as recited in our application filed on the 16th day of September, 1897, Serial No. 651,886, to which cross-reference is here made. In this class of trucks it has been usual to place the pivotal center of the car and truck approximately over .the axle of the larger wheels, so as to preponderate the weight of the car thereon and thereby increase the traction of the truck; and to this end it has also been the custom to sleeve or otherwise mount the motors on or in communication with the axle of the larger wheels and apply the motive power thereto, in which case the large wheels have been termed the driving-wheels of the truck, the smaller wheels being used to allow of the free curving of the truck under the car. In a truck so constituted it has been found in many instances to be exceedingly advantageous to apply a greater braking power to the larger or driving wheels than to the smaller or trailing wheels for the purposes, primarily, of apportioning the braking power applied to the weight on each of the sets of wheels, and, further, for the purpose of arresting the rotation of the wheels nearer to the point where the motive power is ap- Serial No. 625,891. (No model.)

plied in preference to simultaneously apply- 'ing an equal amount of power both upon the driving and trailing wheels.

Other objects had in view by us are to apply the braking power that the tendency of the smaller or trailing wheels to lift and leave the track during the braking operation will be pressure reduced so that such power is apportioned on predetermined lines to the weight of the car, 650., that each set of wheels carry, and through the mechanism hereinafter de scribed the grip of the shoes on either sets of wheels is intermittently released, allowing of considerable intermitted rotation of the wheels while the brakes are on and preventing the flattening of the tread.

Our invention therefore consists in a brake mechanism in which is introduced means for accomplishing the above-stated ends, the particular means hereinafter shown and described consisting of a spring or springs so located in the brake mechanism that either subsequent to or simultaneous with the application of the braking power to one set of wheels said power will be primarily exerted in compressing the spring or springs until the resistance oifered by such spring or springs is equalor properly proportioned to the power which it is desired to apply on the wheels with which such springs are intended to cooperate, at which time the full or desired braking power will be applied to the other set of wheels.

Ourinvention further consists in the details of construction and in the combination of parts hereinafter described ,and further pointed out in the claims.

In the drawings forming part of this specification, Figure 1 is a plan view of the truck equipped with our brake mechanism. Fig. 2 is a-sectional elevation taken approximately along the longitudinal center of the truck, the brake mechanism being at rest and parts of the truck omitted for the sake of clearness. Fig. 3 is an enlarged fragmentary sectional elevation of the brake mechanism on the same plane as Fig. 2, showing the manner of ap plying the brake-shoes to their respective wheels. Fig. 4 is a plan view of a portion of the truck and brake-lever hanger, taken substantially on the line w 00, Fig. 3.

Similar numerals of reference indicate cor responding parts throughout the several views.

Under certain conditions it may be desirable to employ our invention in trucks wherein large and small wheels, or wherein the feature of increased traction is not present, and it is obvious that we therefore do not limit ourselves to itsemployment in maximum or increased traction trucks; but inasmuch as the invention has special application to such class of trucks and produces satisfactory results in its employment thereon we have illustrated the invention in connection with such a truck, which may be constructed as follows:

At 1 2 in the drawings are respectively the driving axle and wheels, and 8 4, respectively, the trailing axle and wheels, both of the axles being provided with journal-boxes 5 and 6 in the usual manner, the journal-boxes being embraced by yokes or pedestals 7 8, forming part of the side frames 9, either of the ends of which may be provided with a cross-bar 10.

In the present case the brake-shoes for the driving-wheels being hung from the truckframe the employment of a cross-bar 10 orits equivalent is essential, the cross-bar being bolted to the ends of the side frames, as illustrated, or in any other desirable manner, and the shoes for the trailing wheels being hung from the truck-frame on the inside to so support them we employ a cross-bar 11, which in this case is made of a flat bar turned edgewise, its ends 12 being bent at an angle, the ends being bolted to the side bars 9, as shown. Such a truck or one otherwise constructed can be employed, the essentials in this regard being merely the means for preserving the parallelism of the axles and wheels and means for hanging the brake-shoes.

The brake mechanism is constructed as follows: To the vertical web 13 of the cross-bar 10 are secured inwardly and upwardly extending hangers 14, provided with an eye and cross-pin 15, from the ends of which, on both sides of the hanger, pivotally depend links 16,-

the lower ends of the links pivotally engaging a pin 17, which extends through an apertured boss 18 on the head 19 of the brake-shoe 20, which shoe is made longer or on a larger arc than the shoe for the trailing wheels, so that the shoes for both sets of wheels will grip a properly-proportioned amount of surface on the respective treads of their wheels.

Thus far the construction of the brake-shoe and its hanging is old.

Each of the shoes 20 is provided with a rearwardly-extending and apertured boss 22, the shoes being connected transversely by a brake beam 23, the ends 24 of which are rounded and pass through the aperture in the boss 22, so as to allow of a vibrational movement on the ends of the brake-beam relative to said shoe or the shoe to vibrate thereon, as the case may be, the beam being provided with apertured enlargements 25 intermediate of the shoes for the connection of the brake-rods, as hereinafter described.

The shoes 26, which cooperate with the small or trailing wheels 4, are supported from the truck-frame on the inside, so as to operate in the same direction of movement as do the shoes 20, and for hanging the shoes like hangers and links are employed as are employed in connection with the shoes 20.

At 27 is another brake-beam, which is also provided with journaled ends finding bearings in the apertured bosses 22 and is further provided with apertured enlargements 25 intermediate of the shoes to allow of the passage of the brake-rod therethrough, as hereinafter described.

We employ for operating the brake-rods upright brake-levers 28, which are fulcrumed at their lower ends in outwardly-projecting U-shaped hangers'or brackets 29,which are in turn secured to the cross-bar 11, pins 30 passing through the hangers and upright levers to form the fulcra for said levers on the hangers.

The brake-power is applied from a Windlass or lever on the car (or in any other suitable way) to the upper ends of the brake-levers 28, and in order to provide for the connection of the brake mechanism and the car Windlass or lever, &c., we employ, by preference, a draft-equalizing lever comprising the transverse and segmental equalizing-bar 31, hav ing ends 32 extending outwardly at an angle thereto, which ends are bifurcated, as at 33, and pivotally secured to the upper ends of the brake-levers 28 by pins 34, the connection between the equalizing-lever and the car-levers, 820., being provided by devices which allow of a movement between said equalizingbar and said levers, as illustrated in the patent to John A. Brill, No. 503,121, dated August 15, 1893.

The connection between the brake-beams and the brake-levers 28 is made as follows: At 35 are duplicate brake-rods extending 1ongitudinally of the truck between the wheels and at the drive-wheel under the drive-axle 1. The drive-wheel ends of the brake-rods (in Figs. 1, 2, and 3) are provided with an exterior thread and pass loosely through the enlargements 25 in the brake-beam 23, the extreme end of the brake-rod being provided with nuts 36, which impingeagainst the face end of each of the brake-rods is bifurcated, thereby forming an upper arm 38, or gooseneck, and a lower arm or thrust-bar 39, the upper arm 38 being bifurcated to embrace the brake-lever 28, to which said arm is pivotally secured by means of the pin 40, the lower arm or thrust-bar 39 having two diameters, the beginning and ending of which forms a shoulder 41, Fig. 3, the forward portion of the bar of smaller diameter 42 passing loosely through the apertured enlargements on the brakebeam 27, the larger portion 43 of the thrustbar being provided with a screw-thread, as is the extension 42, both parts being provided with nuts 44 45, and interposed between the brake-beam 27 and the nuts 44 and about the parts 42 43 of the thrust-bars 39 are spiral springs 46, spring-caps 47 48 being interposed between the respective ends of the spring and the nut 44 and brake-beam '27, the respec-- tive parts 42 43 of the arms39'passing through said caps, the cap 48 especially being movable on the arm 42. By these means the braking power applied to both sets of wheels can be apportioned to the particular work to be accomplished.

The operation is as follows: While at rest I prefer that the shoes 20 shall lie farther away i from the face of the wheels 2 than do the shoes 26 from the wheels 4, (this being attained by adjustment of either or both of the nuts 36 45,) and when power is applied to the upper end of the brake-levers 28 they will be vibrated toward the smaller wheels, pulling, through the connection 38, the shoes 20 toward the face of the wheels 2. At the same time and before the shoes 20 have impinged against the tread of the wheels 2 the shoes 26 will have been brought to bear on the tread of the wheels 4. The shoes 26 having found a bearing against the wheels 4, a continuation of the movement of the shoes 20 toward the Wheels 2 will force the springs 46 forcibly through the arm 39 against the brake-beam 27 with constantly-increasing force as the movement in the same direction of the lever 28 continues, compressing the springs and separating the nuts from contact with the brake-beam 27, and when the shoes 20 are under full or desired pressure on the wheels 2 applying the shoes 26 to the wheels 4 under a pressure bearing the proportion to that exerted on the wheels '2 which may be desired, the greater pressure, as the mechanism is arranged herein, being on the larger wheels and less on the smaller wheels. The application'of the shoes 20 to the treads of the driving-wheels 2 can be direct, as just described, or indirect and through springs, as set forth in said specification, in which latter case the tension of the springs is to be so adjusted that they will not be at the limit of their compression when the shoes find a bearing on the tread of the wheel under ordinary braking pressure.

It is obvious that by adjusting the resiliency of the springs 46 less pressure can be exerted upon -the wheels'4 than is exerted upon the wheels 2 and that thisadjustment can be in a measure obtained by moving the nut 44 on the part 43 of the arm 39 so as to compress or relax the springs 46, or such springs may, if desired, be of such a characteras to be able to sufficiently resist the movement of the arms 39 against the brake-beam, so as to allow of the same degree of power which may be exerted upon the wheels 2 to be exerted upon the wheels 4, and by placing a weaker spring, or by otherwisevarying the resistance interposed by the springs, varying pressure can be brought to bear upon the wheels 4 or cause the pressure to be the same on both wheels.

The nut 45, which is movable upon the extension 42, forins an abutment for the brakebeam to bear against during the pushing of the shoes to the face of the wheels and by means of which the time of application of the shoes 26 to the wheels 4 as compared with that of shoes 20 to wheels 2 can be regulated or adjusted, and the adjustment can be made which will allow of both sets of shoes being applied simultaneously or the shoes 20 before the shoes 26, as desired.

The enlargements 43 of the arms 39 support the springs 46 free from wabbling, and the shoulder 41, formed at the point of union of the parts 42 43, serves as a safety medium, which will insure 'the application of the brake-shoes 26 to the wheels 4 should the connection with the brake-shoes 20 break out or become damaged or the springs 46 be broken or omitted, in which events the shoulder, provided sufficient play of the car-leverspermits, will impinge against the brakebeam 27 and apply the brake-shoes 26 to the wheels 4.

One of the advantageous results flowing from the employment of our invention is that it reduces the flattening of the tread of the small wheels due to the sliding of the wheels on the track while the brake is on, which is a very frequent occurrence, owing to the heavy pressure applied to brake cars in modern street traffic, as the springs 46 will yield sufficiently and intermittently to the power of the sliding wheel to release it and grip it again, thereby allowing of a partial rotation of the wheel and consequent changing of the surface of the wheel exposed to the rail.

We do not intend to limit ourselves to the exact construction shown, as the invention can be embodied in other structures. Nor do we limit ourselves to the employment of the mechanism herein described to trucks of the large and small wheel or maximum traction class, as it is obvious that the device can be applied to the usual class of trucks.

Having described our invention,we claim 1. In a brake mechanism for a truck of the maximum traction class having large and small wheels, and means for'differentiating the brake-pressure exerted upon the large and small wheels, comprising shoes, and connecting means therefor for each of the sets of wheels, a primary lever supported on the truck, a connection between the primary lever and the shoes for the large wheels whereby said shoes are applied directly to the large wheels through the operation of said lever, a movable connection between said primary lever and the shoes of the small wheels, and a spring or springs interposed in said last-mentioned connection to oppose the application of pressure to said smaller wheels, substantially as described.

2. In a brake mechanism for a truck of the maximum -traction class having large and small wheels, of means for applying a differentiated braking pressure on the large and small wheels, comprising shoes, and connecting-beams for each of the sets of wheels, a primary lever supported on the truck, an inflexible connection between said lever and the beam of the large wheel-shoes, an inflexible arm leading from said lever to the beam of the small wheel-shoes, and a spring interposed between said arm and latter beam, substantially as described.

3. The combination with a truck of the maximum traction class having large and small wheels, of the brake mechanism comprising aprimary lever pivoted on the truck, brake-shoes,of beams for connecting the shoes in pairs, a rod connecting said primary lever and the shoe-beam for the large wheels, a supplemental rod between saidfirst-mentioned rod and the shoe-beam for the small wheels and movably connected with said latter beam, both rods moving in the same direction, a spring between the supplemental rod and its beam, and an abutment on said supplemental rod on the other side of the beam, substanti ally as described.

4. In a brake mechanism, the combination with the shoes and means for operating the shoes in the same direction, beams connecting the shoes in pairs, a pair of operating-levers, rods connecting each lever with proximate end of one beam, and a spring between each of said rods and the other beam, said springs being located in advance of the last-mentioned beam, substantially as described.

5. In a brake mechanism, the combination with the shoes, and paired beams connecting the shoes, a brake-rod engaging one beam, an extension 39 from said rod movably engaging the opposing beam, a nut 45 on the end of the extension outside of the latter beam, a spring on the extension abutting against said beam on the side opposite said nut, and a nut 44: on the extension abutting against the opposite end of the spring, substantially as described.

6. In a brake mechanism, the combination with the shoes, and paired beams connecting the shoes, a brake-rod engaging one beam, an extension 39 from said rod movably engaging the opposing beam, a nut 45 on the outer end of the extension, a spring on the extension abutting against said beam on the side opposite said nut, and means on the extension for altering the tension of said spring, said means abutting against the inner end of the spring, substantially as described.

7 The combination with the brake-shoes, of the beams connecting the shoes in pairs, an operating-lever, a brake-rod extending between said beams and movably engaging both of said beams, a connection between the rod and said lever, and a spring interposed between one of the said beams and said rod to oppose the application of its shoes to the wheels, substantially as described.

8. In a brake mechanism, the combination with the shoes and beams connecting said shoes in pairs, of a primary lever fulcrumed at its end, rods extending between one of said beams and secured to said primary lever between its power end and fulcrum, a thrustbar operated by said lever, and a spring or springs interposed between said thrust-bar and the opposing beam, said bar and beam having a movable connection, substantially as described.

9. In a truck brake mechanism, the combination with the shoes adapted to be moved in the same direction, opposing beams connecting the shoes in pairs, one of said beams being located between the wheels, the other outside of the wheels, a brake-rod passing loosely through the beams, means for moving the rod, abutments on the rod, one of the abutments being between the wheels and the other outside of the wheels, and a spring between one of the beams and one of said abutments, sub stantially as described.

10. The combination with the shoes and beams, of the upright lever fulcrumed at its end upon the car-truck, the inflexible brakerod secured to one beam at one end and to the primary lever at its other end between the power end and fulcrum of said lever, an extension of said rod movably engaging the other beam, an abutment on said extension, and a spring between said abutment and said beam, substantially as described.

11. The combination with the shoes, and

beams connecting them, of the primary lever, the brake-rod extending between one of said beams and pivotally secured to said lever, an extension of said rod movably engaging the other beam, an abutment on said extension, a spring interposed between said abutment and said beam, and an abutment on said extension for said beam, substantially as described.

12. The combination of the primary lever, the shoes, and the beams connecting said shoes in pairs, a rod extending between one of said beams and said primary lever, and an extension of said rod movably connected with the other beam, substantially as described.

13. In a brake system, the combination of the brake-shoes, beams, and operating means therefor, of the brake-rod connected at one end with one beam, and at the other with said means, and an extension from said rod connected with anotherbeam of said system, substantially as described.

14. In a brake mechanism, the combination of the brake-shoes, beams, and operating means therefor, of the brake-rod connected at one end with one beam, and at the other with said means, an extension from said rod movably connected with another beam of said system, and a spring interposed between the extension and the latter beam, substantially as described.

15. The combination of the primarylever, the shoes and beams connecting said shoes in pairs, rods extending between one of said beams and said primary lever, and an extension of said rod movably connected with the other beam, a spring on said extension, one end of which abuts against said beam, and the nuts 44, 45 respectively forming an adjustable abutment for said spring and said beam, substantially as described.

16. The combination with the shoes, beams connecting said shoes in pairs, the primary lever, a rod extending between one of said beams and said primary lever, an extension from said rod movably engaging the other beam, a spring on said extension abutting against said beam, and further means on said extension for contacting with said beam, said means being held away from said beam by said spring, substantially as described.

17. The combination with the shoes, and the beams connecting said shoes in pairs, of the primary lever, a brake-rod extending between said lever and one of said beams, an extension from said rod movably engaging the other beam, a shoulder formed on said extension and adapted to engage said beam, an abutment on said extension, and a spring extending between said abutment and said beam, substantially as described.

18. The combination with the cross-bar 11, the hanger 29 extending therefrom, the upright lever 28 fulcrumed at its end to said hanger, the brake-shoes 20 and connectingbeam 23, the shoes 26 and connecting-beam 27, the hanger for supporting said last-mentioned shoes from said cross-bar, a brake-rod 35 secured at one end to the beam 23, said brake-rod having a bifurcated end 38, 39, the upper arm 38 being secured to said brake-lever adjacent the latters fulcrum, the lower arm 39 movably engaging the beam27, an abutment on said arm 39, and a spring interposed between said abutment and said beam, substantially as described.

19. The combination of the shoes 20, a brake-beam movably connected to said shoes at its ends, the upright lever 28, the shoes26, and connecting-beam 27, the forked connecting-rod, one end of which is connected with the beam 23, the upper fork connecting the primary lever, the lower fork movably connected with the beam 27, an abutment on the lower fork, and a spring between said abutment and said beam 27, substantially as described.

20. The combination with the shoes 20 and beam 23, the upright levers 28, the equalizingbar 31 and extensions 32 pivotally'secured to the upper end of said upright levers, forked rods, each of which is secured at one end to the beam 23, the upper fork of each of said rods being secured to one of said upright levers above the latters fulcrum, the lower fork movably engaging the beam 27, an abutment on said lower fork, and a spring between said abutment and said beam, substantially as described.

Signed in the city and county of Philadelphia, State of Pennsylvania, this 26th day of February, 1897.

JOHN A. BRILL. WALTER S. ADAMS. Witnesses:

R. S. REED, CHARLIE STRANGE. 

